Aptitude - Ratio and Proportion - Discussion

Discussion Forum : Ratio and Proportion - General Questions (Q.No. 9)
9.
The sum of three numbers is 98. If the ratio of the first to second is 2 :3 and that of the second to the third is 5 : 8, then the second number is:
20
30
48
58
Answer: Option
Explanation:

Let the three parts be A, B, C. Then,

A : B = 2 : 3 and B : C = 5 : 8 = 5 x 3 : 8 x 3 = 3 : 24
5 5 5

A : B : C = 2 : 3 : 24 = 10 : 15 : 24
5

B = 98 x 15 = 30.
49

Discussion:
125 comments Page 11 of 13.

Deepi said:   1 decade ago
SEE This carefully
a:b1
- b2:c
-----------
a*b2:b1*b2:b1*c=a:b:c

Nisha said:   1 decade ago
Thanks kalpa.

Deepi said:   1 decade ago
Hi Guys,

I have a shortcut method like this kind of problems see this
a:b:c can be calculated easily from a:b and b:c just multiply as shown below
a:b
b:c
-------
a*b:b*b:b*c

So from the problem 2:3 is a:b and 5:8 is b:c
2:3
5:8
-------
2*5:3*5:3*8
answer is 10:15:24

Here given is sum of three number is 98.
that is 10+15+24=49
49=98
15=? => (15*98)/49 = 30.
(1)

RISHIKESH said:   1 decade ago
Thanks alisha.

Murali said:   1 decade ago
If a:b:c=2:3:5 then the ratio of (b+c)/4:(c+a)/4:(a+b)/4 is?
Can any one give answer for this....

Ankur saxena said:   1 decade ago
a/b=2/3,b/c=5/8
a+b+c=98
2b/3+b+8b/5=98
b=30

Sweet said:   1 decade ago
Let a's amount= z
so b's amount=1210-z
now (4/15)z=(2/5)x(1210-z)
=>
(4/15)z=484-2/5z
=>
(4/15)z+(2/5)z=484
=>
by taking l.c.m (10/15)z=484
=> 10z=7260
=>
z=726

So a's amount=z=726

and b's amount=1210-726=484 ans.

Amit said:   2 decades ago
Hey thanks kalpa, its very easy to understand.

Vicky singh said:   2 decades ago
Thanks kalpa for solve such easy method to this question.

Avijeet said:   2 decades ago
Thanks alisha.

You used awesome shortcut:).


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